On the Mechanics and Control of Boundary Layer Transition induced by Discrete Roughness Elements

Transition induced by streamwise arrays of roughness elements on a flat plate in Mach 3.5 flow

“…Work by Suryanarayanan et al. (2017) also showed a cancellation effect if one roughness patch downstream had a similar shape but the opposite orientation to the upstream patch.…”

“…2014; Suryanarayanan et al. 2017). However, to develop these methods, more information is required to determine which instabilities dominate in the wake of a roughness element.…”

“…2014; Suryanarayanan et al. 2017). Much of this work has shown that a distributed roughness pattern seems to be defined primarily by its most prominent features (Downs et al.…”

“…Because the parameter space in which roughness can be defined is large, algebraic correlations typically require tuning or biasing the correlations for each environment, geometry and roughness type (isolated versus distributed) (Reda 2002;Berry & Horvath 2008;Schneider 2008;King, Kegerise & Berry 2009). Semi-empirical methods are also currently being developed for instabilities in the wake of these roughness elements (Choudhari et al 2013;Sharma et al 2014;Suryanarayanan et al 2017). However, to develop these methods, more information is required to determine which instabilities dominate in the wake of a roughness element.…”

“…Studies of isolated roughness elements provide useful information regarding the types of instabilities generated by roughness, but real-world application requires the study of the interaction of these instabilities for surfaces with multiple roughness elements or both a distributed and isolated roughness. The study of the physics of pseudo-random distributed roughness has been extensively carried out in subsonic flow by an experimental group at Texas A&M University (Downs, White & Denissen 2008;Kuester et al 2014) and a computational group at the University of Texas (Drews et al 2011;Sharma et al 2014;Suryanarayanan et al 2017). Much of this work has shown that a distributed roughness pattern seems to be defined primarily by its most prominent features (Downs et al 2008;Drews et al 2011) and that the presence of a distributed roughness can shield an isolated roughness (Kuester et al 2014).…”